Heretofore pipelines, accumulator tanks, surge vessels and other equipment which store, transport, or otherwise handle gas-liquid mixtures such as hydrocarbons, water, and the like which contain one or more of natural gas, carbon dioxide, and the like, have had associated therewith a vent means. Such vent means are used, due to a temporary overload or safety situation or other circumstance, to discharge small amounts of the mixture being handled in that equipment to the atmosphere outside that equipment. This venting is done when the equipment is shut down or overloaded with the gas-liquid mixture to prevent damaging the equipment and creating leaks or worse which would create discharges much greater than the limited, controlled and temporary venting by way of a vent means designed for such a purpose. The vent means are normally a small diameter pipeline connected to the equipment to be vented. Such a pipeline extends for a distance away from the equipment and then terminates in a generally upstanding or otherwise vertical pipe known as a "vent riser". The upper end of the vent riser terminates a substantial distance in the air so that the gas from the gas-liquid mixture, if flammable, can be ignited and burned as a flare to dispose of the gas, the liquid portion falling to the earth's surface for collection and disposal.
It is undesirable to eject the gas-liquid mixture from the vent riser vertically into the atmosphere because this can allow for wider dispersion of the liquid portion. Accordingly, various flare vent heads have been employed at the upper end of vent risers to direct the flow of gas and liquid downwardly. This helps contain the dispersion of liquid, but when a flammable gas is ignited, the flame can and has in various circumstances grown large enough and hot enough that it has done damage to the vent riser itself and even supporting members for the vent riser that extend from the earth's surface part way up the vent riser.